Method of making multiloop v belts



March 26, 1940.

METHOD OF MAKINGMULTILOOP v BELTS Original Filed July 25, 1958 4Sheets-Sheet 1 INVENTORS J. NEwrorv SMITH Jomv M. BIEBEK 34- BYW? ATORNEYS J. N. SMITH ET AL 2,195,126

M r h 26,1940 'J. N. 8mm HAL 2 .1

METHOD OF MAKING MULTILOOP V BELTS j Or'iginaLFiled July 23, 1938 4Sheets-Sheet 2 rooc eooooo 115-8.

aooneemeao v INVENTORS J. NEWTON SMITH BY Jon/v M. BIEIBEE A ORNEYSMarch 26, 1940. .J. SMITH ET AL 2,195,126

METHOD OF MAKING MULTI LOOP V BELTS Original Filed July 2-3, 1938 4Sheets-Sheet s INVENTORS J. N Ew1o- SMITH YJOHN M. 515352 M 7 A TORNEYS'March 26, 1940. J. N. SMITH EIAL 2,195,126

METHOD OF MAKING MULTILOOP V BELTS Original Filed July 23. 1938 4 SheetsSheet 4 INVENTORS J NEWTON SMITH JOHN M. 51525.2

AT ORNEYS Patented Mar. 26, 1940 UNITED STATES 2,195,126 METHOD OFMAKING MULTILOOP V BELTS Joseph Newton Smith,

Bierer, Waban,

Original Divided and ,8 Claims.

This invention relates to multiloop V belts and multiloop V belt drivingmechanism, and the primary object of the invention resides in thedevelopment of a novel system of power transmission which combines theadvantages of the continuous rope driving systemand the multiple V beltdriving system and at the same nates most of the disadvantages present'in these two old and well known systems. This application is a divisionof our copending application Ser. No. 220,884, filed uly 23, 1938.

The continuous rope-driving system of power transmission, employing anendless rope looped. into a plurality of double reaches, has beenknownfor many years and, while such system has cer-v tain advantages,its disadvantages are numerous and include (1) the requirement of largediameter sheaves to carry, the load; (2) tendency of;

the rope to stretch; and (3) serious effect of atmospheric conditions onthe rope and its driving eihciency. V belts, including multiple V belts,have many advantages over rope drives, including (1) high coeilicient ofcontactv friction due to wedging action; (2) high contact friction overa wide range of belt tensions since the wedging action is not entirelydependent on belt tension; (3) efliciency in transmitting underconditions of small arcs of contact and relatively close sheave centers;(4) less exacting requirements in respect to shafting alignment than inthe case of flat belts; (5) quiet operation. Together with suchadvantages, however, multiple V belts as heretofore constructed andoperated have had serious disadvantages, including (1) the requirementsthat all belts of a set shall be exactly equal in length, crosssectional area, and tension modulus;' (2) that unequal distribution ofthe load causes certain of the belts to fail due to overloading; (3)that any individual belt replacementusually requires replacement of theentire set. Summarized, the load carrying efliciency of multiple V beltsdepends on uniform length, size, and tensile modulus, and the fulfillingof such exacting requirements is a manufacturing impossi- 45 bility. I

Our employment that it can be improved V belt system contemplates the ofan endless V belt so constructed looped into a plurality of doublereaches united by loops at their ends and havin the V faces of eachreach extending straight from each loop to an oppos'tely disposed loopwhereby the several reaches and loops provide in effect a plurality of Vbelts adapted to engage grooved sheaves after the manner of knownmultiple V belts. As is hereinafter more specifically de- Mass, WovenHose & Rubber Company, Mass, a corporation of Massachusetts applicationJuly 23,

time elimi- Salem, and John M. assignors to Boston Cambridge,

1938, Serial No. this application October Serial No. 234,004

scribed, this improved belt is constructed with one or more 360transverse twists therein permitting it to be looped in the manner abovestated and run continuously with its V faces in proper contactingengagement with the said sheaves, the belt being adapted to have oneloop thereof carried across the reaches from one outside reach to theother outside reach by suitable means.

Our improved multiloop V belt system embodies all the above enumeratedadvantages of the multiple V belt system as well as the advantages ofthe continuous rope driving system and without having the seriousdisadvantages enumerated. Among the advantages of our novel-belt may beation of the exacting re multiple V belt system and the primaryadvantage of the continuous rope drive system that every reach of thebelt automatically takes an equal share of the load; (2) uniform loadthroughout the load carrying portions of the belt causes the belt towear uniformly whereby replacement is required only when the entirebelt, becomes worn out, the expense of frequent replacement due topartial failures being therebyeliminated; (3) elimination of thenecessity to match belts as is required when using multiple V belts; (4)uniform tension on the entire load carrying portions of the belt isobtained by a single take-up idler acting ontthe return or cross-overloop. Y Theproduction of a novel multiloop V belt and multiloop V beltdriving mechanism of the fiajture above and hereinafter describedcomprises the primary object of our invention. Y v The above defined andother features of the invention will behest understood and appreciatedfrom the following description of preferred em: bodiments thereof,selected for purposes of il-. lustration and shown in the accompanyingdrawings in which I Fig. 1 is a plan view of a V belt driving unitemploying our invention,

Fig. 2 is a side elevation of the driving sheaves, Figs. 3, 4 and 5 areviews showing respectively the strip material usually employed in thecover, compression portion and tension portion of the belt, I

Fig. 6 is a somewhat diagrammatic view in perspective showing the stepof for g the tension portion of the bel 1 Fig. 'l is an enlarged crosssectional view through the formed tension port'on of the belt,

Fig. 8 is a view similar to Fig. 6 and showing belt and the step ofbuilding the compression portion of the belt onto the tension portionthereof,

Fig. 9 is an enlarged cross sectional view through the belt body whichcomprises the combined tension and compression portions,

Fig. 10 is a somewhat diagrammatic view in side elevation showing theshearing of the belt body to V form,

Fig. 11 is an enlarged sectional view taken on line I|'-ll of Fig. 10,

Fig. 12 is a cross sectional view through the sheared belt body,

Fig. 13 is a somewhat diagrammatic view in side elevation showing theapplying of the belt cover to the belt body,

Fig. 14 is an enlarged view taken on line |l|4 him. 13,

Fig. 15 is a somewhat diagrammatic view in side elevation showing thecontinuous vulcanizing of the covered belt,

Fig. 16 is an enlarged sectional view of the completed belt taken online |6-|6 of Fig. 15,

, Fig. 17 is a somewhat diagrammatic plan view showing a modified methodof continuously vulcanizing the belt,

Fig. 18 is a view in side elevation showing the vulcanizing of the beltin a fiat press,

Fig. 19 is a view of the completed belt in side elevation,

Fig. 20 is a plan view of the completed belt in the form it assumes onthe driving unit shown in Fig. 1,

Fig. 21 is a somewhat diagrammatic view showing a modified method ofconstructing the belt,

Fig. 22 is a somewhat diagrammatic view showing the continuous shapingand vulcanizing of the belt to V-form,

Fig. 23 is an enlarged cross sectional view of the belt before beingshaped and vulcanized,

this view being taken on line 23-23 of Fig. 22,

Fig. 24 is a fragmentary sectional view taken on line 24-44 of Fig. 22.

In Fig. 1 we have illustrated a power driving I mechanism employing ournovel multiloop V-belt. This mechanism comprises a base In on which ismounted a driving unit or motor l2 and a driven unit l3, the motor beingadjustable toward and from the unit I 3 under the action of threadedrods l4 and the unit l3 carrying crank arms l5 connected by rods IE tomechanism to be oscillated or reciprocated. The units l2 and I3 areprovided with sheaves l8 and I9 formed with annular V-grooves 20 thereinfor receiving the V-belt.

The belt 2| is one endless piece looped into four double reaches unitedby loops at their ends.

e four loops at one end of the reaches are engaged within the fourannular grooves 20 in the sheave l8 and three of the loops at theopposite end of the reaches are engaged within three annular grooves 20in the sheave l9. The remaining loop extends beyond the sheave l9 and issupported on a sheave 22 carried on a bracket 23 secured to the frame 24which carries the m0- tor. The sheave 22 is mounted to rotate on an axis25 disposed at an angle to the rotary axis of the sheave I 9, and thesheave 22 is of such size as to hold its belt reaches clear of thesheave |9.- The sheave 22 may be termed the cross-over sheave since itspurpose is to carry the belt from the outside groove at to the outsidegroove In Fig. 19 we have condition or shape at the other side thereof.shown the belt 2| in the which it normally assumes and it is looped overtwo supporting rolls one side of the sheave |8 lustratedin Fig. 20, theouter face 26 of the belt faces outwardly throughout the reaches andloops and the belt has two endless V faces 21 converginginwardly fromsaid outer face whereby the said V faces are adapted continuously to runstraight through the sheaves and engage the V grooves thereof in theknown V belts.

We have discovered that a V belt can be looped to provide a plurality ofpairs of reaches and still leave the outer face 26 facing outwardlythroughout the reaches and loops and the V faces converging inwardlytherefrom byplacing one or more 360 transverse twists in the belt. Thenumber of such twists corresponds to the number of additional pairs ofreaches to be provided. For example, if the belt is to have oneadditional pair of reaches, a total of two pairs of reaches, the beltwill be given one 360 transverse twist. The belt 2| has three additionalpairs of reaches therefore provided with three 360 transverse twists as.shown in Fig. 19. Such twists cause the belt properly to engage thesheave grooves and run straight 'therethrough after the manner of knownV belts. The crossover, illustrated by the loop 28 in Fig. 20, can beeffected by any of various known methods and mechanisms.

Our novel V belt can be made by various methods certain of which areillustrated herein. In' all of such methods, however, the belt will begiven one or more 360 transverse twists and, while the belt mightpossibly be constructed in such manner that the twist is givm thereto asa whole, we prefer to construct the same in endless form and apply thetwist thereto during the building up of the belt, all as hereinafterdescribed.

A V belt includes a body having an inner compression portionand an outertension portion.

and this body is enclosed within a suitable cover.

In Figs. 3, 4 and 5 we have shown respectively the 50 up in endless formto give the necessary strength so and provide the belt body, after whichthe cover strip is applied, the 360 twists being given to the strips asthey are appli In Fig. 6, we have illustrated the forming of the tensionportion of the belt.

36 to form an endless band having the strip end 31 fixed there.- toadhesively or in any suitable manner and, as illustrated in Fig. 6, theupper reach of the belt passes through a plurality of rolls 38. While wehave illustrated the relatively angular position of these rolls as being180 successively along the upper reach, it will be understood that anynumber of rolls arranged at suitable angles and on one or both reachesmay same manner as the 13 The strip 321$ pairs of guid ng be provided.The rolls as guide the band as the same is built up from the strip 32and give the necessary 360. transverse'twists thereto. When the band hasbeen built up to the desired strength, the trailing end of the strip isattached thereto and the compression portion .is applied by windingthereonto in like manner the strip 3|, as illustrated in Fig. 8. Thestripsyare all of an adhesive nature and during the plying up next togive the body a V-shape preferably by shearing away sideportions-thereof. This step is illustrated in Figs. 10 and 11 whereinthe band is shown as supported on two rolls 42 with the twist in thelower reach and having the upper reach thereof passing straight throughguides 44 and rotary shearing knives 45. It will be apparent that as theband is driven in the direction of the arrow, the knives will shear theside edges to the V-shape illustratedin Fig. 12. The resulting band 46is now ready to receive the belt cover. 1 s In Fig. 13, the band 46 isshown as supported on two rolls 48 with the twist in the upper reach andhaving the lower reach passing straight across a platform 50. As theband travels'in the direction of the arrow the cover strip 30 is drawntherewith from a roll 5| over a guiding roll 52. Two pairs of rolls 54and 55 thereupon act upon the cover to wrap it about and press it ontothe V-sides of the band, and a roller 56 serves to press the two edgesof the cover into firm adhesive contact with the inner face of the band,

as is best illustrated in Fig. 14. The belt in the form illustrated inFig. 14 is now ready to be vulcanized.

.The belt can be vulcanized by any convenient and suitable method,either continuously as illustrated in Figs. 15 and 1'7 or in. steps asillustrated in Fig. 18. The method illustrated in Fig. 15 embodies theuse of a heated vulcanizing drum 58 V-grooved annularly to receive oneor more belts and having a pressure band 60 passing around a substantialarcuate portion thereof in the manner illustrated and described inPatent No. 2,083,527. The endless belt 6| to be vulcanizedis supportedon the drum and an outer roll 62 with the twists in the upper reachwhereby leaving the lower reach running straight from the roll 62 to thedrum. The drum is rotated slowly in the direction of the arrow whereuponthe belt is run into the V-groove thereof and pressed firmly thereintoby the pressure band 66. The belt is thereby continuously vulcanizedduring its contact passage with the drum beneath the pressure band. Itwill be understood that a plurality of belts may be thus vulcanizedsimultaneously on the drum. The completed belt is illustrated in crosssection in Flg. 16.

It is also possible to vulcanize the belt while holding it in theloopedform in which it is used. This method is illustrated in Fig. 17wherein the belt is supported on two drums 64 and 65 and a cross-oversheave- 66. The drums and sheaves are V-grooved annularly to receive thebelt and ent No. 2,093,904.

the vulcanizing may be performed where the belt engages either drum orwhere it engages the sheave. A pressureband, suchas is shown at 68, willpreferably be provided to cooperate with the beltand force it into thevulcanizing groove or grooves.

The belt may be vulcanized insuccessive steps on a flat press asillustrated inj'Fig. 18. In this case the belt is supported on rolls 10with the twist in the lower reach. The top reach of the belt-runsstraight between the 'two rolls and a fiat press 12 is adapted to engageand vulcanize this straight portion. When one portion of the belt hasbeen vulcanized, the beltis'moved along to bring the adjacentunvulcanized portion thereof to the press in the usual and well knownmanner.

The completed belt is shown in its normal condition in Fig. 19 and inthe form "it assumes on the driving unit in F18. 20.

A modified method of making the belt in looped condition is illustratedin Fig. 21. In this case 'an endless work-supporting band 'I4 passes ina plurality of reaches and loops over two supporting drums l6 and over across-over roll 11, the band 14 being a permanent part of the apparatus.The tension and compression strips..3l and 32 are applied to this bandat 18 and plied up thereon in like manner as illustrated in Figs. 6 and8 to provide an endless beltbody 19 like that illustrated in Figs. 8 and9. This body can then be sheared to the V form, covered and vulcanizedas heretofore. described or it can be covered without shearing, to theform illustrated in cross section in Fig. 23, and thereafter compressedto illustrated in Figs. 22 and 24.

The apparatus used in such treatment may be substantially the same asthat illustrated in Fig. 15'and heretoforev described, the bandsupporting roller together with the pressure band 60 serving to force.the .belt body 19 into the V- groove and mold it to the- V-shape shownin Fig. 24. To serve this function the roller 80 can be pressureoperated through the use of hydraulic; cylinders 82 in like manner as inPat- V-shape during the vulcanizing treatment, as

during its contact passage with the drum beneath the pressure band 60.

It may also be stated that the covered belt shown in Fig. 23 may be madeafter the fashion illustrated in Fig. 21 by first laying the cover 84 inflat form on the band 14 and then building the belt body thereonto, theedge portions of the cover being thereafter wrapped about the belt body.

- The novel V belt of our invention which is the product of the processherein disclosed is not claimed herein, but forms the subject matter ofour copending application above identified.

Having thus described my invention what we claim as new and desire todeclare by Letters- Patent is:

1. The method of making an endless V belt of the multiloop type definedherein, which consists in building up an endless belt body having aplurality of plies by winding suitable strip fabric together with rubberinto overlapping relation The belt body is vulcanized longitudinally ofthe belt while simultaneously therewith giving one or more 360transverse twists to each layer of the fabric, wraping a fabric coveronto the body, and vulcanizing the combined body and cover in contactwith heated V side walls corresponding to the V side walls desired inthe finished belt.

2. The method defined in claim 1 in which the belt is vulcanized bypassing the same continuvously in straight condition to and from saidheated V side walls respectively at spaced points while holding thesection thereof between said points in contact with said heated walls.

3. The method defined in claim 1 in which the belt is vulcanized bypassing the same continuously in straight condition to and from saidheated V side walls respectively at spaced points while holding thesection thereof between said points in contact with said heated walls,and in which the belt is continuously pressed into shaping contact withsaid heated walls as the belt travels to and along the vulcanizing areabetween said spaced points.

4. The method of making an endless V belt of the multiloop type definedherein, which consists in building up an endless belt body having aplurality of plies forming an inner compression portion and a pluralityof plies forming an outer tension portion by winding suitable stripfabric together with rubber into overlapping relation longitudinally ofthe belt while simultaneously therewith giving one or more 360transverse twists to each layer of the fabric, wrapping a fabric coverlongitudinally about the body and the side edge portions thereoftransversely into enclosing contact with the body while giving the cover360 transverse twists corresponding to the twists of the body, andvulcanizing the combined body and cover in contact with heated V sidewalls corresponding to.th e V side walls desired in the finished belt.

5. The method of making the multi-plied body of an endless V belt of themultiloop type defined herein, which consists in forming suitable stripmaterial into an endless band while twisting the strip to form one ormore 360 transverse twists in the band, and winding further stripmaterial in like twisted condition .onto the band to the desiredstrength and thickness.

6. The method of making an endless V belt of the multiloop type definedherein and embodying an inner compression portionand an outer tensionportion, which consists in forming suitablestrip material into anendless band while twisting the strip to form one or more 360 transversetwists in the band, winding further strip material in like twistedcondition longitudinally onto the band to form one of said portions,winding strip material of another character in like twisted conditiononto said one portion to form the other portion, placing a coverstrip onthe combined portion, and simultaneously shaping and vulcanizing theresulting unit to the desired V shape throughout its length.

7. The method of making an endless V belt of the multiloop type definedherein and embodying an inner compression portion and an outer tensionportion, which consists in forming suitable strip material into anendless band while twisting the strip to form one or more 360 transversetwists in the band, winding further strip material in like twistedcondition longitudinally onto the band to form one of said portions,winding strip material of another character in like twisted conditiononto said one portion to form the other portion, shearing the combinedportions to form endless V sides therealong, placing a cover strip onthe sheared portions, and vulcanizing the resulting unit to the desiredV shape throughout its length.

8. The method of making an endless V belt of the multiloop type definedherein, which consists in supporting a strip of suitable cover materialin a plurality of double reaches united by loops at their ends, windingstrip material substantially narrower than the cover strip in pliedcondition longitudinally onto the cover strip to form an endless band.body of the desired strength and thickness, wrapping the covertransversely about the band body, and simultaneously shaping andvulcanizing the resulting product to the desired V shape throughout itslength.

J. NEWTON SMITH 7 JOHN M. BIERER.

